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Literature summary extracted from

  • Schlegel, B.P.; Ratnam, K.; Penning, T.M.
    Retention of NADPH-linked quinone reductase activity in an aldo-keto reductase following mutation of the catalytic tyrosine (1998), Biochemistry, 37, 11003-11011.
    View publication on PubMed

Protein Variants

EC Number Protein Variants Comment Organism
1.6.5.10 D50N less than 0.1% of wild-type activity Rattus norvegicus
1.6.5.10 H117A less than 0.1% of wild-type activity Rattus norvegicus
1.6.5.10 K84M complete loss of activity Rattus norvegicus
1.6.5.10 K84R complete loss of activity Rattus norvegicus
1.6.5.10 Y55F narrow substrate specificity, reduction of selected aromatic quinones and alpha-dicarbonyls. The activation energy for 9,10-phenanthrenequinone reduction is unchanged in Y55 mutants Rattus norvegicus
1.6.5.10 Y55S narrow substrate specificity, reduction of selected aromatic quinones and alpha-dicarbonyls. The activation energy for 9,10-phenanthrenequinone reduction is unchanged in Y55 mutants Rattus norvegicus

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
1.6.5.10 0.002
-
 9,10-phenanthrenequinone wild-type, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.012
-
 9,10-phenanthrenequinone mutant D50E, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.014
-
 9,10-phenanthrenequinone mutant Y55F, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.026
-
 9,10-phenanthrenequinone mutant Y55S, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.044
-
 9,10-phenanthrenequinone mutant H117A, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.056
-
 9,10-phenanthrenequinone mutant D50N, pH 6.0, 25°C Rattus norvegicus

Organism

EC Number Organism UniProt Comment Textmining
1.6.5.10 Rattus norvegicus P23457
-
-

Renatured (Commentary)

EC Number Renatured (Comment) Organism
1.6.5.10
-
 Rattus norvegicus

Source Tissue

EC Number Source Tissue Comment Organism Textmining
1.6.5.10 liver
-
 Rattus norvegicus
-

Specific Activity [micromol/min/mg]

EC Number Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
1.6.5.10 0.000003
-
 substrate (R,S)-camphorquinone, mutant Y55F, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.00002
-
 substrate (R,S)-camphorquinone, mutant Y55S, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.0006
-
 substrate acenaphthenequinone, mutant Y55F, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.0006
-
 substrate acenaphthenequinone, mutant Y55S, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.0016
-
 substrate 9,10-phenanthrenenquinone, mutant Y55S, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.0018
-
 substrate 9,10-phenanthrenenquinone, mutant Y55F, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.0025
-
 substrate (R,S)-camphorquinone, wild-type, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.0038
-
 substrate acenaphthenequinone, wild-type, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.0044
-
 substrate 9,10-phenanthrenenquinone, wild-type, pH 6.0, 25°C Rattus norvegicus

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
1.6.5.10 (R,S)-camphorquinone + NADPH + H+
-
 Rattus norvegicus (R,S)-camphorquinone + NADP+
-
 ?
1.6.5.10 9,10-phenanthrenequinone + NADPH + H+
-
 Rattus norvegicus 9,10-phenanthrenequinol + NADP+
-
 ?
1.6.5.10 acenaphthenequinone + NADPH + H+
-
 Rattus norvegicus acenaphthenequinol + NADP+
-
 ?
1.6.5.10 additional information enzyme displays bifunctional 3alpha-hydroxysteroid dehydrogenase and NADPH reductase (quinone) activities. Quinone reduction occurs via a mechanism that differs from 3-ketosteroid reduction. In this mechanism, the electron donor NADPH and acceptor o-quinone are bound in close proximity, which permits hydride transfer without formal protonation of the acceptor carbonyl by Tyr 55 Rattus norvegicus ?
-
 ?

Synonyms

EC Number Synonyms Comment Organism
1.6.5.10 AKR1C9
-
 Rattus norvegicus
1.6.5.10 More bifunctional 3alpha-hydroxysteroid dehydrogenase and NADPH reductase (quinone) Rattus norvegicus

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
1.6.5.10 0.01
-
 9,10-phenanthrenequinone mutant D50N, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.02
-
 9,10-phenanthrenequinone mutant D50E, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.04
-
 9,10-phenanthrenequinone mutant H117A, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 1.45
-
 9,10-phenanthrenequinone mutant Y55F, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 1.45
-
 9,10-phenanthrenequinone mutant Y55S, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 2.85
-
 9,10-phenanthrenequinone wild-type, pH 6.0, 25°C Rattus norvegicus

pH Optimum

EC Number pH Optimum Minimum pH Optimum Maximum Comment Organism
1.6.5.10 additional information
-
 the pH dependency of 9,10-phenanthrenequinone reduction catalyzed by the wild-type enzyme is different to that observed for 3-ketosteroid reduction. The kcat value for 9,10-phenanthrenequinone reduction is pH-dependent with the maximal rate decreasing with increasing pH but reveals an ionizable group with a pKb of 8.90 that must be protonated for maximal activity Rattus norvegicus

Cofactor

EC Number Cofactor Comment Organism Structure
1.6.5.10 NADPH
-
 Rattus norvegicus

kcat/KM [mM/s]

EC Number kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
1.6.5.10 0.06
-
 9,10-phenanthrenequinone mutant Y55S, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 0.1
-
 9,10-phenanthrenequinone mutant Y55F, pH 6.0, 25°C Rattus norvegicus
1.6.5.10 1.43
-
 9,10-phenanthrenequinone wild-type, pH 6.0, 25°C Rattus norvegicus